一种4站情况下基于TDOA/FDOA的无源定位方法

在基于时频差的三维运动目标无源定位系统中，针对在4个接收站的情况下搜索法实时性低的问题，提出了一种基于改进的加权最小二乘法（MWLS）与萤火虫算法（FA）相结合的无源定位方法（MWLS-FA）。该方法的第1步通过构造一组新的方程来对加权最小二乘（WLS）方法进行改进，使得改进后的WLS方法在4站情况下也能得到目标位置和速度的初始值，第2步利用这个初始值为FA方法提供一个动态的搜索区域，同时在约束条件的添加和参数选择两个方面针对性地对FA方法做出了调整和改进。仿真结果表明，该方法在4站情况下对目标的定位精度可以达到克拉美罗下限（CRLB），而且在实时性和抗噪性方面优于传统的搜索法，同时该方法在5站情况下的抗噪性能优于两步加权最小二乘法（TSWLS）和约束加权最小二乘（CWLS）法。

Passive location method based on TDOA/FDOA in case of 4 receivers

A new joint location method (MWLS-FA), combining the Modified Weighted Least Squares (MWLS) method and the Firefly Algorithm (FA), is proposed to solve the poor timeliness problem in the case of 4 receivers in the three-dimensional moving target passive location system based on Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA). This method first modifies the Weighted Least Squares (WLS) method by constructing a new set of equations, such that the MWLS method can also obtain the initial values of the target position and velocity in the case of 4 receivers. Then, this initial value is used to provide a dynamic search area for the FA method which is also adjusted and improved in adding constraints and selecting parameters. Simulation results show that the accuracy of the proposed method can reach the Cramer-Rao Lower Bound (CRLB), and is remarkably better than the traditional search methods in terms of timeliness and noise resistance. Meanwhile, the accuracy of this method is superior to Two-Step Weighted Least Squares (TSWLS) and Constrained Weighted Least Squares (CWLS) in the case of 5 receivers.